This is the 9290th most frequent Polish word.
trójką
"Trójką" means "triangle" (in the instrumental case) in English.
The word "trójką" refers to a triangle, describing the shape made by the fish.
Widziałem trójką ryb w akwarium.
I saw a triangle of fish in the aquarium.
Here, "trójką" is used to describe a group of three people participating.
Graliśmy w grę na trójką osoby.
We played a game with a trio of people.
In this example, "trójką" again refers to a triangle, emphasizing its application in a geometric context.